Generally, a vacuum pump (compressing device) which includes rotary compressing elements in a casing is known. In this kind of vacuum pumps, a vacuum can be obtained by driving the rotary compressing elements with a driving device such as an electric motor.
A vane-type vacuum pump is known as the compressing device. In this kind of vacuum pumps, a vacuum can be obtained by driving rotary compressing elements with a driving device such as an electric motor.
Generally, it is known that the vacuum pump includes a casing attached to the wall surface of the driving machine, a rotor which is rotationally driven by the rotary shaft of the driving machine in the casing, and a plurality of vanes which are extendably accommodated in the rotor. In this kind of vacuum pumps, a vacuum can be obtained by driving the rotor and the vanes in the casing with a driving machine such as an electric motor.
The vacuum pump is carried, for example, in an engine room of an automobile and is used to produce a vacuum to operate a brake boosting device (for example, refer to a PTL 1).
Further, it is known that a vacuum pump includes a casing attached to a driving machine, a hollow cylinder chamber which is formed in the casing and has openings at the two ends of the casing, a rotor which is provided at the rotary shaft of the driving machine and which is rotationally driven in the cylinder chamber with the rotary shaft, and a pair of side plates which block the openings of the cylinder chamber. This kind of vacuum pump is used to produce a vacuum to operate, for example, a brake boosting device of an automobile, and the vacuum can be obtained by driving the rotor in the cylinder chamber of the casing with the driving machine such as an electric motor (for example, refer to a PTL 2).